<?php
abstract class BaseRequest
{
	var $from_id;
	var $to_id;
	var $page_size;
	var $page_index;
	
	function __construct($request)
	{
		$this->from_id = isset($request['from_id']) ? $request['from_id'] : '';
		$this->to_id = isset($request['to_id']) ? $request['to_id'] : '';
		$this->page_size = isset($request['page_size']) ? $request['page_size'] : '';
		$this->page_index = isset($request['page_index']) ? $request['page_index'] : '';
	}
	
	abstract function is_valid();
}